Printing presses of the above-mentioned type are already known in the art, for instance from Swiss Patent No. CH 685 380 A5, European Patent Publications Nos. EP 0 406 157 A1, EP 0 415 881 A2, EP 0 563 007 A1, EP 0 873 866 A1, and International Publications Nos. WO 03/047862 A1, WO 2008/146193 A1, WO 2011/077348 A1, WO 2011/077350 A1, WO 2011/077351 A1, all assigned to the instant Applicant.
In the above printing presses, a problem may arise in respect of the accessibility of part of the inking devices, in particular of the uppermost and lowermost inking devices. It may in particular be difficult for an operator to perform setting-up, inspection and maintenance operations of the lowermost inking device which is typically hidden by the inking device that is located immediately above it.
An attempt to solve this problem is disclosed in European Patent Publication No. EP 1 088 657 A1. This publication more precisely discloses an intaglio printing press with four chablon cylinders acting as ink-applying cylinders and a corresponding number of inking devices, wherein the lowermost inking device and associated chablon cylinder are supported by a first sub-frame capable of moving toward and away from a main frame supporting the ink-receiving cylinder (namely an intaglio cylinder or an ink-collecting cylinder of the intaglio printing press). The three remaining inking devices (i.e. the inking devices other than the inking device that is supported by the first sub-frame) are supported by a second sub-frame, distinct and independent from the first sub-frame, which is also capable of moving towards and away from the main frame. In addition, the three remaining chablon cylinders (i.e. the chablon cylinders other than the chablon cylinder that is supported by the first sub-frame) are supported by the main frame or, as the case may be, by the second sub-frame.
A problem with the solution described in European Patent Publication No. EP 1 088 657 A1 resides in the fact that the first sub-frame not only supports the lowermost inking device, but also the associated, lowermost chablon cylinder. This is not ideal from the point of view of the register accuracy between the chablon cylinder and the ink-receiving cylinder with which the chablon cylinder cooperates, and one rather prefers to support all chablon cylinders within the same frame as the ink-receiving cylinder. This furthermore unnecessarily complicates the driving interconnection between the chablon cylinder and the ink-receiving cylinder.
A further problem with the solution described in European Patent Publication No. EP 1 088 657 A1 resides in the fact that the first sub-frame can be moved to its retracted position only after the second sub-frame has been moved to its retracted position. This means that setting-up and inspection operations of the lowermost inking device specifically require the other inking devices to be retracted by moving the second sub-frame to its retracted position (as shown in FIG. 2(b) of EP 1 088 657 A1), which unnecessarily complicates setting-up, inspection and maintenance operations.
An improved solution is thus required.